Partial Peptide of [alpha]-Synuclein Modified with Small-Molecule Inhibitors Specifically Inhibits Amyloid Fibrillation of [alpha]-Synuclein

We have previously reported that pyrroloquinoline quinone (PQQ) prevents the amyloid formation of α-synuclein, amyloid β1-42 (Aβ1-42), and mouse prion protein. Moreover, PQQ-modified α-synuclein and a proteolytic fragment of the PQQ-modified α-synuclein are able to inhibit the amyloid formation of α-synuclein. Here, we identified the peptide sequences that play an important role as PQQ-modified specific peptide inhibitors of α-synuclein. We demonstrate that the PQQ-modified α-Syn36-46 peptide, which is a partial sequence of α-synuclein, prevented α-synuclein amyloid fibril formation but did not inhibit Aβ1-42 fibril formation. In addition, the α-synuclein partial peptide modified with other small-molecule inhibitors, Baicalein and epigallocatechin gallate (EGCG), prevented α-synuclein fibril formation. Currently reported quinone amyloid inhibitors do not have selectivity toward protein molecules. Therefore, our achievements provide a novel strategy for the development of targeted specific amyloid formation inhibitors: the combination of quinone compounds with specific peptide sequence from target proteins involved in amyloid formation.